Cystic fibrosis is caused by mutation in the cystic fibrosis transmembrane conductance regulator (CFTR). In the lung the site of highest expression of CFTR is in the submucosal gland cells of the airways. These cells express high levels of the polymeric immunoglobulin receptor (pIgR), a receptor that endocytoses IgA at the basolateral surface and transcytoses IgA to the apical surface. We propose to use the pIgR to target vectors for expression CFTR to the submucosal gland cells. We will use monoclonal antibodies directed against the extracellular domain of the pIgR. Intact IgG or monovalant Fab' fragments will be coupled to various vectors. Two vector systems that will be tried are a liganded adenovirus system developed by David Curiel, and a amphiphillic polymer system developed by Frank Szoka. We will use the vectors to deliver and express either a trial reporter gene (beta-galactosidase) or the CFTR, driven by a cytomegalovirus vector. We will start by using Madin-Darby canine kidney cells that have been transfected with the rabbit pIgR. When grown on a permeable support, these, cells form a polarized monolayer that mimics an in vivo epithelial monolayer. If successful we will then use primary cultures of airway submucosal gland cells. Ultimately we will try an intact rodent model.